Inflatable packers that comprise an elastomeric bladder are well known and are used in attempts to seal off sections of a wellbore. The bladder defines a chamber that contains a pressurized fluid which is used to inflate the packer while the elastomeric body seals against the wellbore and prohibits annular fluid flow past the packer when in the inflated position. Problems with inflatable packers include loss of the seal between the packer body and the wellbore. Factors that affect the reliability of the seal include pressure differentials, incomplete inflation, seal leaks and compressibility.
Therefore, it is a desire to provide a dynamic inflatable sealing device wherein the bladder is maintained at a pressure substantially equal to or greater than the pressure in the annulus between the packer body and the wall of the wellbore. It is a still further desire to provide a dynamic inflatable sealing device that maintains the bladder a pressure substantially equal to or greater than the highest annular pressure encountered. It is a still further desire to provide a dynamic inflatable sealing device that provides a full internal diameter passageway thus maintaining full fluid flow and the ability to pass equipment through the passageway.